Airplane automatic control



June 9, 1931. A. E. ELsEA 1,808,771

AIRPLANE AUTOMATIC CONTROL Filed Sept. 20. 1929 2 Sheets-Sheet l 5 "I WW" L June 9, 1931,

A. E. ELSEA AIRPLANE AUTOMATIC CONTROL Filed Sept. 20. 1929 2 She-ets-Sheet 2 42 O ZZ o u/A/ VEA/roe: 6155er ,6. A55/9.

Patented June 9, 1931 UNITED STATESr PATENT OFFICE Application nled September 20, 1929. Serial No. 888,950.

My invention has relation to improvements in airplane automatic controls and consists in the novel features of construction more fully set forth in the speciiication and polnted out 1n the claim. l

Briefly, thev invention comprises a gravlty or electric actuated mechanism that may be connected to the cables between the control stick and ailerons, and stick and elevator for automatically restoring the plane to even keel if tilted by adverse air currents on either its vertical or transverse axis. The control may replace the usual control stick or be operated in connection with it, and embodies an 1nd1- cator for displaying the angle of bank or inclination.

The automatic control has for its principal object the righting of the plane without the aid ofthe manual controls, at the same time indicating the degree of departure from equilibrium. It is also an object of the invention to provide an automatic control that may be used as an accessory, without disturbing the standard controls. A further object of the invention is to provide a device capable of accomplishing the above objects with promptness and precision; and to provide a device that is simple and rugged. Further advantages will be better apparent from a detailed '30 description of the invention in connection with the accompanying drawings, in which- Figure 1 is a diagrammatic view of the ailerons and elevator, or ap, of an'airplane together with their connections, and my improved automatic control assoclated therewith; Fig. 2 is a rear elevation of the control with parts of the housing broken away; Fig.

3 is a vertical cross-section taken on the line 3-3 of Fig. 2; Fig. 4 is a front elevation of 4 l the control with part of the housing broken away; Fi 5 is a fragmentary section of a modified orm of the invention adapted for actuation by an electric motor; Fig. 6 is a fragmentary view looking at right angles to Fig. 5; Figs. 7 and 8 are vertical sectlons,

taken at right angles to each other, of a control switch associated with the modified control shown in Figs. 5 and 6; Figs. 9 and 10 are vertical section and front elevation of a 5 modification in which the device is used only` asA a bank indicator; and Fig. 11 is asimilar lmodification showing the device used as an as shown. The elevator flaps d, d are actuated by cables e, e connected to rock-levers f, f mounted on shaft g which has connection with the stick c through the lever h and connecting rod z'. A second automatic control C may be connected to one of the levers f by short cables j, y' and an anchor lever k. The manner of connecting the controls C, C is immaterial and I make no claim to the specific connections herein shown. It is also of no consequence whether the usual control stick c is retained, my improved control being used as an auxiliary thereto, or replaced by my automatic control. The essential thing in the present invention is the automatic control and its indicator now about to be described.

Referring to Figs. 2, 3, and 4 of the drawings, the invention comprises a casing having a top wall 1, a bottom wall 2, end walls 3 and 4, a rear cover plate 5, and a. front cover plate 6. End walls 3 and 4, havebearings 7 and 8 formed in them respectively and a supporting spider 9 is provided in the casing in spaced relation with rear wall 5 so as to 85 divide the casing into compartments 10 and 11. 'A recess 12 is provided at the center of spider 9 to receive a ball-bearing 13 and a recess 14 is formed at the center of cover plate6 to receive a ball-bearing 15, in which bearings is mounted a shaft 16. A pendant A lever 17 having a hub 18 at one end and a weight 19 at thev outer, free end is freely mounted on the shaft 16 by means of the ballbearings 20, and said lever is adapted to be coupled to the shaft 16 through a clutch 21 slidingly mounted on shaft 16 through -a spline 22. A toothed annular recess 23`fis formed in the hub 18 for engagement withzthe toothed extension 24 on the clutch 21V and a 1 l I tion of the device is o is tilted or banked laterally, not by the will shift lever 25 has connection at its upper bifurcated end 26 with an annular ve 27 formed in the clutch 21, whereby the latter may be put into and out of en a ment with the hub 18 of lever 17. A shi r 26 traverses an opening 27 in cover plate 6 and has `its inner end connected at 28 to the extremity of shift lever 25- for actuating the shift lever, and a spring clamp 29 projects from the mside of rear plate for t e purpose of engaging the lever 2 5 and holding it when it has been moved to bring the clutch 21 and hub 18 into en vement. A 30 is fixed ony the end o aft 16 that'projects into the com artment and has one end of a connecting rod 31 pivotally connected near its periphe The front end of saidconnectrodrgeing pivotally connected to an eye 32 formed in a bar 33 slidingly mounted in bearings 7 and 8. The ends o bar 33 may be connected by clevises 34, 34 to cables b, b which operate the ailerons a, a. A dash-pot 35 is pivotally connected at its outer end to a lug 36 projecting from top wall 1 of casing C, the plunger 36 of the pot being connecte to connectin rod 31 and disk 30 by means of a link 37. f course, the dash-pot may be either h draulic or pneumatic and of any standar ty A control handle 38 is fixed by means o -a key 39 to the forward end of shaft 16 said key also serving to secure an indicator wheel 40 in slightly spaced relation with the handle 38, and a casing or cover 41 for the wheel is secured to cover plate 6 by means of screws 42' tranversing a flange 43. The indicator wheel cover 41 has an arcuate window 44 extending over an anle of slightly more than 180 throughwhich' e indicator wheel may be observed, and any desired graduations may be placed upon the indicator wheel to show the pilot the amount of bank that is being made by the plane to either the left or right. Such markings would be readable with references to a center line 45 on the window 44. In order that the dial readin may be useful in the event that the plane s ould assume an inverted position, that half of the dial that is normally the lower half could be of a different color from the half that is normally the upper half. Obviously, the markings may laced uplon the cylindrical surface of the in icator w eel and the window through which such markin are readable would be on the correspon ing surface of the casing as shown in Fig. 11, which will bev more specifically referred to hereinafter. v l l From thev foregoingl descri tion the operavious. en the plane of the operator but by adverse air currents, the lever arm under the influence of weight 19 will maintain its verticalit-y while the cas- C will move with the c plane' therefore tion will be imparted to the disk 30 and 30 and reci rocate bar 33 to actuate the ailerons or e evator flap as the case may be. Of course, when the control handle 38 is used for the manual control of the plane the lever arm 17 is referably disconnected by iiing the shift ar 26 and thus releasing Yin 18 from the clutch 21.

In Figs. 5 to 8 inclusive, I show a modification of the invention in which electrical means are substituted for the gravity o rnl; I

ated weight 19 for actuating the device. he

lever arm 17 has a toothed segment 50l formed on the outer end for engagement with a worm 51 mounted on a motor shaft 52 suppprted in bearings 53, 53 together with the arings of motor 54. The motor is electrically connected to stationary contacts 55, 55, 55, 55 fixed in the contact case 56 of a housing 57, and to a rotary contact 58 mounted on one end of a shaft 59 havin suitable bearings in the housing 57. A weight 60 is sus ended from a lever arm 61 connected to a-s aft 59 within housing 57, andwith a relative movement between the weight and the housing, the

movable contact 58 will ride over the inner cylindrical surface of contact case 56. Thus when the housing 57 is mounted in an airplane and the latter is banked the roller contact 58 will rotate, and if the movement is sufficient to either side, it will engage one of the contacts 55 and close the electrical circuit through the motor 54 puttin the motor into operation and oscillating the lever 17 to actuate the ailerons for the purpose of righting the plane. The construction of the control switch for the motor 54 is not arbitrary and in the present instance is similar to that of an electric distributor in the ignition system of internal combustion engines. The essential feature of such a control switch is the relativel fixedzand rotatable contacts, the latter being actuated by the gravity lever 61.

In Figs. 9 and 10 I show the rinciple of the invention applied to a ban indicator without the automatic control feature. In this modification the indicator wheel 65 has a weight 66 built into it at one' point, and is freely rotatable on bearings 67, 68 in a cylindrical casing 69. The casing 69 is provided with an arcuate window 70 through which the graduations on the wheel .65 may be road. In Fi 11 I show an indicator similar to that s own in Figs. 9 and 10 except that the window 71 is provided on the cylindrical wall of casin 69 instead of the front flat wall, thereby a apting the device to be used more advantageously as an indicator for the angle of climb and descent.

While my improved control is primarily adapted to airplanes it may be used to similar advantage on dirigibles especially to prevent automatically the ship from nosing upward or downward under the influence m of rising and falling air currents. When the device is used on dirigibles it will be connected to the elevator controls in a manner similar to that employed on airplanes.

Having described my invention, I claim: 16 An aircraft control comprising acasing adapted to be ved in the aircraft, a shaft mounted in said casing,l a pendant lever loosely mounted on said shaft, means for coupling the lever to the shaft, an indicator 20 fixed to the shaft, said indicator bein readable in connection with suitable marklngs on the casing, a manually operable lever fixed to. said shaft, and connecting mechanism operable by said shaft and adapted to be con- 25 nected to the aircraft stabilizing devices.

In testimony whereof I hereunto affix my signature.

ALBERT E. ELSEA. 

